Protective arrangement



N. SEN SUI PROTECT I VE ARRANGEIENT Dm 11, 192s. 1,694,986

Filed Feb. 1, 1927 Inventor Nobuo Sensui,

by M@ 2,427

His Attorney.

Patented Dec. 1l, 1928.

UNITED STATES PATENT OFFICE.

NOBUO SENSUI, OF KANAGAWAKEN, JAPAN, ASSIGNOR 'lO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW' YORK.

PROTECTIVE ARRANGEMEN T.

Application ed February 1, 1927, Serial My invention relates to improvements in protect-ive arrangements, and more partlcularly to improvements in balanced protective arrangements for a plurality of parallel lines.

In balanced protective arrangements for parallel lines, when a line is disconnected, it is desirable to eliminate the protective apparatus of the line from the protective arrangement so as properly to maintain the balanced feature in the protective apparatus of the lines remaining in service. As previously done, the mere reclosing of the interrupting means at one end of a line has served to restore the protective apparatus of the line at said end. With this arrangement, if the interrupting means at both ends are not closed simultaneously, trouble arises due to the fact that the interrupting means first closed is operated on a balanced basis but without an actual balance. In consequence, particularly if the lines in service are heavily loaded, whenever an attempt is made to put a line in service, if the interrupting means at the receiving end is closed first, it is apt to be tripped, or if the interrupting means at the tnansmitting end is closed first, the lines already in service are apt to be disconnected. To avoid this difficulty, since it is not an economically feasible matter to insure simultaneous closing of the interrupting means at both ends, the protective relays have been given such settings that the eiiiciency of the protection peculiar to the balanced protective arrangement is decreased, since the possible sensitivity of operation is sacrificed.

An object of my invention is to provide an improved protective arrangement wherein all the features of the balanced protection of parallel lines are utilized to the greatest extent, and wherein the difliculties heretofore set forth are eliminated.

Another object of my invention is to provide an improved balanced protective arrangement wherein'the control of the protective apparatus is such that continuity of service on sound lines is not impaired on the occurrence of unbalanced conditions.

My invention will be better understood from the following description, taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the single figure of the accompanying drawing, there is diagrammatically illus- No. 165,200, and in Japan April 20, 1926.

trated a balanced protective arrangement embodying my invention, and shown in single line diagram for clearness. In this illustrated embodiment of my invention, busses 1 and 2 are arranged to be connected by a plurality of parallel lines such as feeders 3, 4, 5, which are arranged to be controlled by suitable circuit controlling means, herein shown as comprising interrupting means such as circuit breakers 6 to 11 inclusive. Each of the circuit breakers 6, 7, and 8 is shown as equipped with a trip coil 12 and auxiliary switches 13 and 14, which are open when the circuit breakers are open and closed When the circuit breakers are closed.

For controlling the circuit breakers 6, 7 and 8 at one end of the lines, a balanced protective arrangement is provided. As illustrated, this arrangement comprises cooperating electroresponsive devices, such as power directional relays 15, 16, 17 and overcurrent relays 18, 19, 20. These protective relays are connected to respond to an unbalance in the line currents so as selectively to efect the opening of the circuit breaker in the line causing the unbalance. Although the arrangement is shown at only one end of the lines, it is of course understood that it may be provided at both ends and also that the power directional relays may in some cases be omitted.

For energizing the relays, the balanced protective arrangement further comprises transformers 21, 22, 23, arranged to be energized in accordance with the currents of the lines 3, 4, 5 respectively. These transformers are constructed and arranged so as to have their secondaries normally provide equal currents, and the secondaries are connected in a closedor loop circuit in series cumulative, that is, for circulating current under normal line conditions. In order to energize the protective relays in accordance with the imbalance or differential current due to any line abnormality, the current windings 24, 25 of the relays associated with each line are connected across the secondary of the current transformer associated with the line. The potential winding 26 of the power directional relays may be energized through transformers 27 connected to the bus 1.

In order to render the controlling means or protctive apparatus associated with a line inoperative on disconnection of the line at l 'ne connc's and 3 are open when lre ceneeenerglzed, chat is. when Vllre ll'r e' rne'n crcuil contro A one posen. nini cloeeffl when 'lle ergzerl. llxaz is. lre cil-cnil conm: member o' the relay is in anorhe position.

lie co 2c S 33 are cleeefl when lre conlrol 20 relay cleencrglze. y men *when if; ie enerelzerl. the conlrol relnye For en :incl also lre ercn Vlier rp coils, e ser; able Source enclr as :1 control lmet Ill provided. The corali-nc@ or elle control relay 1n enen lure are Menge-Ll v, hen cloeecl Snort ur incl-ruling ghe-rein *ghe secondrornrer in che ssocleftecl line. l of eacll conrol relay are cle .rlrel :1re arrange-fel in Se e Winfllnfr of Llre cenl'rel relay n. sriclr la? of llre e corresponelmg' lure across l n l'hs We. i1 ille co1 X 0reil when Jhe L c cir- 1 remain enersrzerl lier @genes and llevrebjr ecrire zrpoereus conl'rollng u (D L CA 50 connected acros l'lre SQ@ @FAHR Jelar energrzecl. lli efe corresponding Y ille crcur'c cenrollrng nestelen only7 'when the el boll enes en (l curil when l' i also to eliminare llrer loud. Q9, Z-O :1re arranged when ,l i c :lecnersrimlion of the This mm.' beklone ne shown 74'? "y eonl'uc's felf lle control refee. sleri" crcull' alle 'windings c nin; relays. Y r, c Y n Shown in The L iene Aleo.' all lines discel elec T5 the eneinnn ol lling) 'lr-euer Si. An

To :lo rhis. i er closed. 'Ille 1' ef closing if; in:n

` l. ce the regl-orme re 1y 35n ls nolo 90 c ,nt lleve in 'l'lxe line a. 1y is energlxes. operates prel :ly nflunrmleonsly :unl "es: 3S cenple the elrent 'llrS relaj,v also o1" niinllyr lne'lrz'n'lenc l Switch le el il The closing el1 lille contacts remy 253 slmrrcjrcnff 'rlxie 9" 'E rvlrcl'l is; 'ellerclore only The opening of 'lle rel@v 28 removes f c u'rent windings l5 Ruil lg. fall '"5 each line ner nl vice7 Aille Secondary @fr the cnrrcnl treneille Seconflmrlef; of the lranee or nee already in service. nt lines 3 n nl el :Nevin :servlnclwllng elle seco nll lers n series cumulative :.ff: illollofs: secondary ol' l, eolnlnclor 3 conl'nce 2. o 1 w relay el). wennen rele.;v 28, een

duc'er with open, the sealing-in circuit of the control relay 29 is interrupted, and this relay is consequently deenergized. The closing of the contacts 33 of this relay short-circuits the current responsive windings 24 and 25 of the protective relays 16 and .19. The opening of the contacts 32 of the control relay 29 removes the short-circuit on the restoring relay 36, so that it is again ready to respond When current is flowing in the line 4. The transformer 22 is now removed from the loop circuit, which is secondary of transformer 2l, conductor 39, contacts 33 of controlrelay 29, conductor 41 contacts 32 of control relay 30, conductor 44, secondary of transformer 23, conductors 45 and 42, contacts 32 of control relay 28 and conductor 43. The balanced protective feature is, therefore, yestablished for the lines 3 and 5, which remain in service, and Will be maintained for these lines until current flow occurs in the other line'4 or lines when the balance feature will be expanded to include the additional line or lines as heretofore explained.y

Although I have shown three lines in single line diagram for elearness, the application to more or less than this number, as well as to the other phase conductors of the lilies, will be obvious to those skilled in the art.

While I have shown and described my invention in considerable detail, I do not Wish to be limited to the exact arrangement shown, but seek to cover in the appended claims all those modifications that fall Within the true spirit and scope of my invention. y

What I claim as new and desire to secure by Letters Patent of the United States, is z- 1. In an electric system wherein parallel lines are arranged to be disconnected at both ends and wherein a protective arrangement is provided at one end for selectively disconnecting a. faulty line, means for rendering the protective apparatus of a line inoperative on disconnection of the line at one end and electroresponsive means arranged to be energized momentarily only on reconnection of the line at both ends for automatically restoring the protective apparatus of said line to the operative condition.

2. In an electric system for parallel lines, a balanced protective arrangement for selectively disconnecting a faulty line, means for rendering the protective apparatus of a line inoperative on disconnection of the line at one end and electroresponsive means arranged to be energized momentarily only when the line circuit is reestablished at both ends for automatically restoring said line protective apparatus to the operative condition.

3. In an electric system for parallel lines, a balanced protective arrangement for selectively disconnccting a faulty line, means for rendering the protective apparatus of a line inoperative on disconnection of the line at one end and means arranged to be energized momentarily ona flow of current in said line for restoringl the protective apparatus thereof to 4interrupting the lines at both ends, means associated with said lines for controlling the interrupting means at one end operative in responseA to unbalanced currents in said lines selectively to ope the interrupting means in the line causing the imbalance, means for rendering the controlling means associated with a disconnected line inoperative and means responsive to the current in the line for restoring said controlling means to the operative condition and maintaining the same in said con dition as long as the interrupting means at said end ofthe line is closed.

5. In combination, parallel lines, interrupting means therefor, and elcctroresponsive circuit controlling means operative in response to unbalanced currents in said lines selectively to effect the opening et the interrupting means in the line causing the imbalance including transformers arranged to be energized in accordance with the currents in the respective lines, a circuit including the secondaries of the transformers connected in series, a relay for each line connected across the secondary of the transformer associated with the line, means operative to one position by the opening of the interrupting means of a line for removing from said circuit the transformer and the relay associated With the disconnected line and to another position in response to a re-establishment of current flow in the line for restoring the relay and the transformer kto said circuit.

6. In combination, parallel lines, means for interrupting the lines at both ends and means for controlling the interrupting means at one end including transformers arranged to be energized in accordance with the currents in the respective lines, a circuit including the transformer secondaries connected in series, a protective relay for each line connected across the secondary of the transformer associated With the line, means operative on the opening of the interrupting means in a line at said end to short circuit the transformer and the protective relay associated with said line and means associated with said line for opening said short circuit When the interrupting means at both ends of the line are closed, and comprising a relay arranged to be energized momentarily in accordance With the current in the line.

7. In combination, parallel lines, means for interrupting the lines at both ends. means associated With said lines for controlling the interrupting means at one end operative in response to unbalanced currents in said lines selectively to open the interrupting means in the line causing the imbalance, means for rendering the controlling means associated with a disconnected line inoperative and electroresponsive means arranged tc he, energized momentarily When the interrupting means at both ends ot the line are closed tor restoring said controlling means to the operative condit-ion.

S. In an electric system comprising parallel lines, a protective arrangei'nent tor selectivehv disconnecting a faulty line, controlling means operative to one position on disconnection ot a line at one end tor rendering;l the protective apparatus associated with the line at said end inoperative and to another position iiorr` restoring the line protective apparatus to the operative condition and maintaining said apparatus in said con tion long; as the line is connected at said enti and meansr operative in response to a tion' et current in said line ttor actuating said coutrolling means to said other position.

9. In an electric system including` parallel lines, a protective arrangement tor selectivelv disconnecting' a faulty line. electroresponsive means operative to One position on disconnection ot a line at one end to render the protective apparatus associated With the line at said end inoperative and to another position in response to a ow of current in the line to restore the line protective apparatus to the operative condition and to maintain the saine in said operative condition as long as the line is connected at said end.

10. In an electric system comprisingr parallel lines, interruptingr means therefor and a balanced protective arrangement tor selectivelyY disconnecting av line causing unhalance including control nieans 'for each line arranged to he deenergized hv the opening ot the circuit interrupting means ot the line iter rendering the protective apparatus essociated with the line inoperative. a relai' open atii'e in response to a 'flow ot line current for energizing said control means \,vh 1\reliv to restore the line protective apparatus to the operative condition arranged to he deenergif/:ed in response to the enerfzization ot control means, and means tor nniiutainiug the control means energized as longy as the interrupting means ot the line is closed.

ln Witness n'herei'it, I have hereunto set in)7 hand this 11th dav of Januarym 1927.

NOBUO SCSUI. 

